This application is to competitively renew the Tri-Institutional ENdocrine Research TRaining Program (ENTRAP) at Weill Medical College of Cornell University (WMC), Memorial Sloan Kettering Cancer Center (MSKCC) and Rockefeller University (RU). The aim is to provide positions for eight highly qualified post-doctoral trainees a year (generally four trainees a year for a two year period) for multidisciplinary training in laboratory investigation in endocrinology, to prepare them for independent careers in biomedical research in academia or industry. The program began in 1978 and expanded to include the three closely connected institutions in 1983. Dr Maclaren has assumed ENTRAP directorship since the previous Director, Marvin C. Gershengorn, MD, left to head the intramural diabetes program at NIH. Of a total of 67 postdoctoral fellows, 44 have been trained in the last 10 years: 13 were MDs; 4, MD/PhDs; and 27, PhDs. Of the 38 who have completed their training, 22 have academic research positions, 9 are in the pharmaceutical industry while 7 are in non-research positions (6 MDs have academic clinical appointments). ENTRAP will closely integrate with long-existing adult and pediatric clinical endocrine training programs, and will actively seek trainees from ethnic minorities. The ENTRAP faculty comprises 18 highly productive scientists who have successful track records as mentors: 5 are from WMC, 4 are from MSKCC and 9 from RU. The scientific disciplines covered include: immunoregulation in health and in autoimmune endocrinopathies; cell surface and receptor biology, lipid raft formation; signal transduction regulation; regulation of transcription; stem cell biology, functional genomics; genomic linkage; lipoprotein metabolism; genetics of obesity, insulin resistance and diabetes; and neuroendocrinology. Whereas the primary training occurs through the laboratory group that the trainee has joined, each fellow will benefit from being part of the ENTRAP enterprise through its regular seminars, annual scientific meeting and access to cutting edge technologies through the laboratories of the whole faculty and the institutional cores. The faculty will elect new members through a majority vote; the executive committee (Maclaren WMC; McEwen RU and Kolesnick MSKCC) will be responsible for selecting trainees with ex-officio assistance from Drs New (WMC), Robbins (MSKCC) and Gershengorn (NIH). The strengths of the ENTRAP continue to be the concordance of the three outstanding component institutions, the continued investigative excellence of the faculty, the successful track record of the program and the variety and depth of research expertise and mentorship available to trainees.